JP2001192533A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition for semiconductor sealing which does not contain a halogen-containing flame retardant and an antimony compound and is excellent in moldability and in flame retardance, high- temperature storage characteristics, reliability of moisture resistance, and resistance to soldering crack. SOLUTION: This resin composition essentially comprises (A) an epoxy resin, (B) a phenol resin, (C) a cure accelerator, (D) an inorganic filler, (E) a solid solution of a metal hydroxide of formula (1): Mg1-xM2+(OH)2 (wherein M2+ is at least one kind of divalent metal ion selected from the group consisting of Mn2+, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+; and 0.01<=x<=0.5) in an amount of 1-15 wt.% based on the composition, and (F) an ion scavenger of formula (2): MgaAlb(OH)2a+3b-2c(CO3).dH2O (wherein 0<b/a<=1; 0<=c/b<1.5; and d is a positive number) in an amount of 0.2-3 wt.% based on the composition, provided the sum of ingredients D, E, and F accounts for 70-93 wt.% of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation which does not contain a halogen-based flame retardant and an antimony compound and has excellent flame retardancy and high-temperature storage characteristics, and a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are mainly sealed with an epoxy resin composition. These epoxy resin compositions contain a halogen-based flame retardant and an antimony compound in order to impart flame retardancy. However, development of an epoxy resin composition having excellent flame retardancy without using a halogen-based flame retardant and an antimony compound is demanded from the viewpoint of environment and hygiene. Further, when a semiconductor device sealed with an epoxy resin composition containing a halogen-based flame retardant and an antimony compound is stored at a high temperature, a thermally decomposed halide is liberated from these flame retardant components and the semiconductor element is bonded. Is known to corrode the semiconductor device and impair the reliability of the semiconductor device.
There is a demand for an epoxy resin composition that can achieve a flame retardant grade of V-0 of UL-94 without using a halogen-based flame retardant and an antimony compound as the flame retardant.

[0003] As described above, the corrosion resistance of the bonding portion (bonding pad portion) of a semiconductor element after storing a semiconductor device at a high temperature (for example, 185 ° C or the like) is called high-temperature storage characteristics. As a method for improving the characteristics, a method using diantimony pentoxide (Japanese Patent Laid-Open No.
146950) and a method of combining antimony oxide with an organic phosphine (Japanese Patent Application Laid-Open No. 61-53321) have been proposed and their effects have been confirmed. On the other hand, some types of epoxy resin compositions are not satisfactory. Further, by using a combination of a specific metal hydroxide and a specific metal oxide, or a composite metal hydroxide of a specific metal hydroxide and a specific metal oxide as a flame retardant, the flame retardancy is improved. There have been proposals to solve the moisture resistance reliability (Japanese Patent Application Laid-Open Nos. 10-251486 and 11-11).
No. 945, etc.), in order to exhibit sufficient flame retardancy, a large amount of addition is required, and therefore, there is a problem that the moldability and the solder crack resistance are deteriorated, and the moisture resistance reliability is also sufficient. Not really. That is, there is a need for an epoxy resin composition that maintains flame retardancy, is excellent in moldability, high-temperature storage characteristics, moisture resistance reliability, and solder crack resistance, and does not use a halogen-based flame retardant and an antimony compound.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a semiconductor encapsulation which does not contain a halogen-based flame retardant and an antimony compound and has excellent moldability, flame retardancy, high-temperature storage characteristics, moisture resistance reliability and solder crack resistance. An epoxy resin composition and a semiconductor device obtained by encapsulating a semiconductor element using the same are provided.

[0005]

The present invention provides (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator,
(D) Inorganic filler, (E) 1 in the total epoxy resin composition
To 15% by weight of the metal hydroxide solid solution represented by the general formula (1) and (F) 0.2 to 3% by weight in the total epoxy resin composition.
% By weight of the ion scavenger represented by the general formula (2) as an essential component, and the total amount of (D), (E) and (F) is 70 to 93% by weight in the total epoxy resin composition; _1-x M ²⁺ _x (OH) ₂ (1) (where M ²⁺ is Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu
^Represents at least one kind of divalent metal ion selected from the group consisting of ²⁺ and Zn ²⁺ , and x represents a number of 0.01 ≦ x ≦ 0.5) Mg _a Al _b (OH) _{2a + 3b -2c} (CO ₃ ) _c · dH ₂ O (2) (where 0 <b / a ≦ 1, 0 ≦ c / b <1.5, and d is a positive number), more preferably the general formula (1) Wherein M ^{2+ of the} metal hydroxide solid solution represented by the general formula (2) is Zn ²⁺ or Ni ²⁺
Is an ion scavenger represented by Mg _4.3 Al ₂ (OH) _12.6 C
An epoxy resin composition for encapsulating a semiconductor characterized by being O ₃ .3.5H ₂ O, and a semiconductor device characterized by encapsulating a semiconductor element using the same.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention refers to all monomers, oligomers and polymers having two or more epoxy groups in one molecule, and their molecular weight and molecular structure are not particularly limited. For example, biphenyl type epoxy resin, bisphenol type epoxy resin,
Stilbene epoxy resin, phenol novolak epoxy resin, cresol novolak epoxy resin, triphenolmethane epoxy resin, alkyl-modified triphenolmethane epoxy resin, epoxy resin containing triazine nucleus, dicyclopentadiene-modified phenol epoxy resin, phenol aralkyl Type epoxy resin (having a phenylene skeleton, a diphenylene skeleton and the like) and the like, and these may be used alone or in combination.

The phenolic resin used in the present invention includes:
Monomers, oligomers, and polymers generally having two or more phenolic hydroxyl groups in one molecule are not particularly limited in molecular weight and molecular structure. For example, phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol Resins, terpene-modified phenolic resins, triphenolmethane-type resins, phenol aralkyl resins (having a phenylene skeleton, diphenylene skeleton, and the like) and the like can be used alone or in combination. Of these, phenol novolak resins, dicyclopentadiene-modified phenol resins, phenol aralkyl resins, terpene-modified phenol resins, and the like are particularly preferable. The ratio of the number of epoxy groups in all epoxy resins to the number of phenolic hydroxyl groups in all phenolic resins is preferably 0.8 to 1.3.

As the curing accelerator used in the present invention, any one can be used as long as it promotes a curing reaction between an epoxy group and a phenolic hydroxyl group, and those generally used for a sealing material can be used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, 2-methylimidazole, tetraphenylphosphonium / tetraphenylborate and the like can be mentioned, and these may be used alone or as a mixture. Absent.

As the inorganic filler used in the present invention, those generally used for a sealing material can be used. For example, fused silica, crystalline silica, talc, alumina, silicon nitride and the like can be mentioned, and these may be used alone or in combination. As the compounding amount of the inorganic filler,
It is preferable that the total amount of the metal hydroxide solid solution and the ion scavenger and the inorganic filler is 70 to 93% by weight in the total epoxy resin composition in view of the balance between moldability and solder crack resistance. If it is less than 70% by weight, the solder cracking resistance decreases with an increase in the water absorption, and if it exceeds 93% by weight, problems such as wire sweep and pad shift are caused, which is not preferable.

The metal hydroxide solid solution represented by the general formula (1) used in the present invention acts as a flame retardant, and its flame retarding mechanism is such that the metal hydroxide solid solution starts dehydration and absorbs heat during combustion. This inhibits the combustion reaction. In addition, it is considered that the flame retardant layer that promotes carbonization of the cured resin component and blocks oxygen on the surface of the cured product is formed. Further, the metal hydroxide solid solution of the present invention has an effect of appropriately lowering the endothermic onset temperature and improving the flame retardancy. If the endothermic start temperature is low, the moldability and reliability are adversely affected, and if the endothermic start temperature is higher than the decomposition temperature of the resin component, the flame retardancy decreases, but the endothermic start temperature of the metal hydroxide solid solution of the present invention is reduced. Is an appropriate value around 300 to 350 ° C. Of these, particularly preferred M ²⁺ are Ni ²⁺ and Zn ²⁺ . The compounding amount of the metal hydroxide solid solution of the present invention is preferably from 1 to 15% by weight, more preferably from 1 to 10% by weight, based on the whole epoxy resin composition. If it is less than 1% by weight, the flame retardancy is insufficient, and if it exceeds 15% by weight, the solder crack resistance and the moldability are undesirably reduced. The average particle size of the metal hydroxide solid solution of the present invention is 0.5 to 30 μm.
And more preferably 0.5 to 10 μm.

The ion scavenger represented by the general formula (2) is
When highly dispersed in the epoxy resin composition, it has flame retardancy, so that the flame retardancy is improved as a synergistic effect with the metal hydroxide solid solution, and the blending amount can be reduced.
As a result, flame retardancy can be maintained even if the blending amount is reduced, and a decrease in moldability and strength, an increase in water absorption, and the like can be prevented. Particularly preferably, Mg _4.3 Al ₂ (OH) _12.6 CO ₃
· 3.5H is a ₂ O. The compounding amount of the ion scavenger represented by the general formula (2) of the present invention is preferably 0.2 to 3% by weight in the whole epoxy resin composition. If it is less than 0.2% by weight, the moisture resistance is insufficient, and if it exceeds 3% by weight, the curability is remarkably reduced, the water absorption is increased, and the solder crack resistance is remarkably reduced. Further, in addition to the ion scavenger represented by the general formula (2) of the present invention, phosphoric acid, organic acid anion, halogen anion, alkali metal cation,
Other ion scavengers for scavenging alkaline earth metal cations and the like can be used in combination. Examples of ion scavengers that can be used in combination include Bi ₂ O ₃ .nH ₂ O, Zr (HPO ₄ )
₂ · H ₂ O, Ti (HPO ₄ ) ₂ · H ₂ O, (NH ₄ ) ₃ Mo
₁₂ (PO ₄ ) ₄₀ nH ₂ O, Ca ₁₀ (PO ₄ ) ₆ (O
H) ₂ , BiO (OH) _0.7 (NO ₃ ) _0.3 , BiO (O
_{H) 0.74 (NO 3) 0.1} 5 (HSiO 3) 0.11, BiO (O
H) and the like, and these may be used alone or as a mixture. The amount of the ion scavenger that can be used in combination is 0.1 to 1% by weight in the total epoxy resin composition.
Preferably, if it exceeds 1% by weight, the curability decreases.

[0012] The metal hydroxide solid solution and the ion scavenger are
Each of them has the property of imparting flame retardancy even if used alone, but a large amount of compounding is required to express sufficient flame retardancy. However, if it is blended in a large amount, the moldability and strength tend to decrease, and the water absorption tends to increase, and the solder crack resistance decreases. In order to prevent these physical properties from deteriorating, it is necessary to reduce the compounding amount as much as possible. The present inventor has found that the combined use of the metal hydroxide solid solution and the ion scavenger of the general formula (2) further improves the flame retardancy as a synergistic effect, and can reduce the amount of the compound. Each of the flame retardants has an endothermic effect at the time of combustion, and further, a metal hydroxide solid solution is
It is believed that the ion scavenger of the general formula (2) promotes carbonization of the cured resin component, has a function of trapping combustible gas, and contributes to flame retardancy. Further, the ion scavenger has an effect of preventing corrosion of aluminum and improving moisture resistance reliability by trapping ionic impurities contained in a resin component, a metal hydroxide solid solution and the like. Although the reason is not clear, the combined use of both makes it possible to complement each other's abilities and obtain high flame retardancy as a synergistic effect. As a result, flame retardancy can be maintained even if the blending amount is reduced, and a decrease in moldability and strength, an increase in water absorption, and the like can be prevented.

The epoxy resin composition of the present invention comprises (A)
The component (F) is an essential component, but if necessary, a silane coupling agent, a coloring agent such as carbon black, a release agent such as natural wax and synthetic wax, and a low stress such as silicone oil and rubber. Various additives such as additives may be appropriately compounded. In addition, the epoxy resin composition of the present invention is prepared by mixing the components (A) to (F) and other additives sufficiently and uniformly using a mixer or the like, and then melt-kneading with a hot roll or a kneader. , After cooling and pulverized. Various electronic components such as semiconductor elements are encapsulated using the epoxy resin composition of the present invention, and semiconductor devices are manufactured by curing and molding using conventional molding methods such as transfer molding, compression molding, and injection molding. do it.

[0014]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to these examples. The mixing ratio is by weight. In addition, the epoxy resin used in the Examples and Comparative Examples,
Abbreviations and structures of the phenolic resin and the ion scavenger are summarized below. Epoxy resin (E-1): ortho-cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., softening point 62 ° C,
Epoxy equivalent 198 g / eq) Epoxy resin (E-2): Biphenyl type epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., melting point 95 ° C., epoxy equivalent 191 g / eq) Phenol resin (H-1): Phenol novolak resin (Softening point 83 ° C, hydroxyl equivalent 104) Phenol resin (H-1): phenol aralkyl resin (softening point 75 ° C, hydroxyl equivalent 175) Ion scavenger (I-1): Mg _4.3 Al ₂ (OH) _12.6 C
O ₃ · 3.5H ₂ O (Kyowa Chemical Co., Ltd., DHT) Ion scavenger (I-2): BiO (OH) _0.7 (NO ₃ )
_0.3 (Toagosei Co., Ltd.)

Example 1 Epoxy resin (E-1) 95 parts by weight Phenol resin (H-1) 50 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 2 parts by weight Fused spherical silica 710 parts by weight Metal hydroxide solid solution (Mg _0.8 Zn _0.2 (OH) ₂ , average particle size 1 μm) 120 parts by weight Ion scavenger (I-1) 10 parts by weight Epoxysilane coupling agent 5 parts by weight Carbon black 3 parts by weight of carnauba wax 5 parts by weight at room temperature using a super mixer, 70 to 10
Roll kneading was performed at 0 ° C., followed by cooling and pulverization to obtain an epoxy resin composition. The obtained epoxy resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Spiral flow: Spiral flow was measured using a mold for measuring spiral flow according to EMMI-1-66 at a mold temperature of 175 ° C., a pressure of 70 kg / cm ² and a curing time of 120 seconds. Curability: Using a JSR Curastometer IVPS manufactured by Orientec Co., Ltd., the diameter of the die was 35 mm, the amplitude angle was 1 °, the molding temperature was 175 ° C., and the torque value after 90 seconds from the start of molding was measured. The smaller the value, the slower the curing. The unit is kgf · cm. Flame retardancy: A test piece (127 mm × 12.7 mm × 3.2 mm) was molded using a low pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² and a curing time of 120 seconds, and 175 ° C. as an after-bake. , After treatment for 8 hours, ΔF and Fmax were measured according to the UL-94 vertical method,
Flame retardancy was determined. Water absorption: A test disk (diameter 50 mm, thickness 4 mm) was molded using a low-pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² , and a curing time of 120 seconds. After that, 150
Dry at 16 ° C for 16 hours, 85 ° C, 85% relative humidity
168 hours, the percentage of increase in weight relative to the initial weight was determined. Units%. Solder crack resistance: 80 pQFP (2 mm thick, chip size 9.0 mm × 9.0 mm) was molded using a low pressure transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² , and a curing time of 120 seconds, followed by after-baking. After treatment at 175 ° C for 8 hours, 85 ° C and relative humidity of 8
96 hours processing at 5%, IR reflow processing (24
(0 ° C., 10 seconds). Using an ultrasonic flaw detector, defects such as peeling and cracks inside the package were observed. The number of defective packages in the six packages is shown. High-temperature storage characteristics: using a low-pressure transfer molding machine, molding temperature 175 ° C., pressure 70 kg / cm ² , curing time 12
16pDIP in 0 seconds (chip size 3.0mm × 3.5
mm), and after-baked at 175 ° C. for 8 hours, subjected to a high-temperature storage test (185 ° C., 1000 hours).
The increased package was determined to be defective. The percentage defective in 15 packages is shown as a percentage. Units%. Moisture resistance reliability: Using a low pressure transfer molding machine, molding temperature 175 ° C, pressure 70 kg / cm ² , curing time 120
1 with a simulation device (without passivation film) in seconds
A 6pDIP (chip size: 3.0 mm × 3.5 mm) was molded, treated at 175 ° C. for 8 hours as an after-bake, and then 5.5 V was applied at 130 ° C. and a relative humidity of 85% to measure open circuit failure. It was expressed as the time when half of the packages were defective. The evaluation was performed up to 1000 hours. The unit is time.

Examples 2 to 7, Comparative Examples 1 to 7 According to the formulations shown in Tables 1 and 2, an epoxy resin composition was obtained in the same manner as in Example 1 and evaluated in the same manner as in Example 1.
The results are shown in Tables 1 and 2. The epoxy equivalent of the brominated bisphenol A type epoxy resin used in Comparative Example 1 was 365
g / eq. .

[Table 1]

[0018]

[Table 2]

[0019]

According to the present invention, an epoxy resin composition for encapsulating a semiconductor which does not contain a halogen-based flame retardant and an antimony compound and has excellent moldability can be obtained. Excellent high temperature storage characteristics, moisture resistance reliability and solder crack resistance.

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Claims (4)

[Claims] 1. An epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, and (E) 1 to 15% by weight of the general epoxy resin composition in the total epoxy resin composition. 1)
And (F) an ion scavenger represented by the general formula (2) as an essential component in the total epoxy resin composition, and (D) and (E). ) And (F) in a total amount of 70 to 93 in the total epoxy resin composition.
An epoxy resin composition for encapsulating a semiconductor, which is contained in a weight percentage. Mg _1-x M ²⁺ _x (OH) ₂ (1) (where M ²⁺ is Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu
^Represents at least one kind of divalent metal ion selected from the group consisting of ²⁺ and Zn ²⁺ , and x represents a number of 0.01 ≦ x ≦ 0.5) Mg _a Al _b (OH) _{2a + 3b -2c} (CO ₃ ) _c · dH ₂ O (2) (where 0 <b / a ≦ 1, 0 ≦ c / b <1.5, and d is a positive number) 2. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein M ^{2+ of the} metal hydroxide solid solution represented by the general formula (1) is Zn ²⁺ or Ni ²⁺ . 3. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein the ion scavenger represented by the general formula (2) is Mg _4.3 Al ₂ (OH) _12.6 CO ₃ .3.5H ₂ O. object. 4. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.